Liposomal and Targeted Drug Delivery System

Liposomes are a novel drug delivery system (NDDS), which are vesicular structures consisting of hydrated bilalyers which form spontaneously whenphospholipids are dispersed in water. They are simple microscopic vesicles in which an aqueous volume is entirely enclosed by a membrane composed of lipid bilayers. Novel drug delivery system aims to deliver the drug at a rate directed by the needs of the body during the period of treatment, and channel the active entity to the siteof action. It has been a study interest in the development of a NDDS. Liposomes are colloidal spheres of cholesterol non-toxic surfactants, sphingolipids, glycolipids, long chain fatty acids and even membrane proteins and drug molecules or it is also called vesicular system. It is differ in size, composition and charge. It is a drug carrier loaded with great variety of molecules such as small drug molecules, proteins, nucleotides and even plasmids. Few drugs are also formulated as liposomes to improve their therapeutic index. Consequently a number of vesicular drug delivery systems such as liposomes, niosomes, transfersomes, and pharmacosomes were developed. The focus of this review is to the various method of preparation, characterization of liposomes, advantages and applications etc.